In a typical mobile communication system, various methods for system level synchronization have been conducted in order to increase network efficiency and reduce power consumption.
For example, when a base station includes a Global Positioning System (GPS), the base station may perform an operation of synchronizing the base station with communication target devices by using a global time point according to the GPS as a reference. However, mobile ad-hoc networks or Device-to-Device (D2D) networks do not include a separate GPS, and thus have difficulty in performing synchronization according to the above-described method.
Particularly, in unlicensed frequency bands, legacy devices operating in different communication standards coexist. Accordingly, devices intending to perform D2D communication in unlicensed frequency bands all require a specific synchronization scheme in which the devices can perform the D2D communication while the devices coexist with the existing legacy devices.
Accordingly, a method and an apparatus for synchronization for unlicensed Device-to-Device (D2D) communication in a case where legacy devices coexist is desired.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.